Example embodiments relate to an analog-to-digital converting circuit and an accumulation circuit including the analog-to-digital converting circuit, and more particularly, to an analog-to-digital converting circuit capable of performing analog-to-digital conversion on an analog input signal without delay, and an accumulation circuit including the analog-to-digital converting circuit.
An analog-to-digital converting circuit converts a continuous analog signal to a discrete digital signal. The analog-to-digital converting circuit converts a received analog voltage or a received analog current to a digital signal corresponding to the analog voltage or the analog current. The analog-to-digital converting circuit requires a conversion period or duration to convert an analog input signal to a digital signal. The conversion period of a given analog-to-digital converting circuit causes the frequency of an input signal which may be properly converted to be limited according to the Nyquist sampling theory.
Examples of conventional analog-to-digital converting circuits include a flash analog-to-digital converter (ADC), a pipelined ADC, and a successive approximation ADC.
A flash ADC converts an analog input signal to a digital signal by using a plurality of comparators having different threshold voltages. The flash ADC performs fast conversion, but requires a large chip area, consumes a lot of power, and is expensive due to the use of a plurality of comparators. The pipelined ADC outputs a digital code for an analog input signal by sequentially converting parts of the analog input signal to digital signals. The pipelined ADC performs fast conversion, but may cause a delay or latency in the conversion. The successive approximation ADC converts an analog input signal to a digital signal according to a method of sequentially correcting a plurality of bits included in a digital signal in the order from a most significant bit to a least significant bit. The successive approximation ADC may have a reduced chip area and consume less power, but the conversion period or duration increases by an amount of time corresponding to the number of bits of the digital signal.